diff mbox series

[v7,29/39] lpm: use C11 alignas

Message ID	1709574764-9041-30-git-send-email-roretzla@linux.microsoft.com (mailing list archive)
State	Accepted, archived
Delegated to:	David Marchand
Headers	From: Tyler Retzlaff <roretzla@linux.microsoft.com> To: dev@dpdk.org Cc: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>, Bruce Richardson <bruce.richardson@intel.com>, Chengwen Feng <fengchengwen@huawei.com>, Cristian Dumitrescu <cristian.dumitrescu@intel.com>, David Christensen <drc@linux.vnet.ibm.com>, David Hunt <david.hunt@intel.com>, Ferruh Yigit <ferruh.yigit@amd.com>, Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>, Jasvinder Singh <jasvinder.singh@intel.com>, Jerin Jacob <jerinj@marvell.com>, Kevin Laatz <kevin.laatz@intel.com>, Konstantin Ananyev <konstantin.v.ananyev@yandex.ru>, Min Zhou <zhoumin@loongson.cn>, Ruifeng Wang <ruifeng.wang@arm.com>, Sameh Gobriel <sameh.gobriel@intel.com>, Stanislaw Kardach <kda@semihalf.com>, Thomas Monjalon <thomas@monjalon.net>, Vladimir Medvedkin <vladimir.medvedkin@intel.com>, Yipeng Wang <yipeng1.wang@intel.com>, Tyler Retzlaff <roretzla@linux.microsoft.com> Subject: [PATCH v7 29/39] lpm: use C11 alignas Date: Mon, 4 Mar 2024 09:52:34 -0800 Message-Id: <1709574764-9041-30-git-send-email-roretzla@linux.microsoft.com> In-Reply-To: <1709574764-9041-1-git-send-email-roretzla@linux.microsoft.com> References: <1707873986-29352-1-git-send-email-roretzla@linux.microsoft.com> <1709574764-9041-1-git-send-email-roretzla@linux.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: list Errors-To: dev-bounces@dpdk.org
Series	use C11 alignas \| [v7,00/39] use C11 alignas [v7,01/39] eal: use C11 alignas [v7,02/39] eal: redefine macro to be integer literal for MSVC [v7,03/39] stack: use C11 alignas [v7,04/39] sched: use C11 alignas [v7,05/39] ring: use C11 alignas [v7,06/39] pipeline: use C11 alignas [v7,07/39] net: use C11 alignas [v7,08/39] mbuf: use C11 alignas [v7,09/39] hash: use C11 alignas [v7,10/39] eventdev: use C11 alignas [v7,11/39] ethdev: use C11 alignas [v7,12/39] dmadev: use C11 alignas [v7,13/39] distributor: use C11 alignas [v7,14/39] acl: use C11 alignas [v7,15/39] vhost: use C11 alignas [v7,16/39] timer: use C11 alignas [v7,17/39] table: use C11 alignas [v7,18/39] reorder: use C11 alignas [v7,19/39] regexdev: use C11 alignas [v7,20/39] rcu: use C11 alignas [v7,21/39] power: use C11 alignas [v7,22/39] rawdev: use C11 alignas [v7,23/39] port: use C11 alignas [v7,24/39] pdcp: use C11 alignas [v7,25/39] node: use C11 alignas [v7,26/39] mldev: use C11 alignas [v7,27/39] mempool: use C11 alignas [v7,28/39] member: use C11 alignas [v7,29/39] lpm: use C11 alignas [v7,30/39] ipsec: use C11 alignas [v7,31/39] jobstats: use C11 alignas [v7,32/39] bpf: use C11 alignas [v7,33/39] compressdev: use C11 alignas [v7,34/39] cryptodev: use C11 alignas [v7,35/39] dispatcher: use C11 alignas [v7,36/39] fib: use C11 alignas [v7,37/39] gpudev: use C11 alignas [v7,38/39] graph: use C11 alignas [v7,39/39] ip_frag: use C11 alignas

Checks

Context	Check	Description
ci/checkpatch	success	coding style OK

Commit Message

Tyler Retzlaff March 4, 2024, 5:52 p.m. UTC

  The current location used for __rte_aligned(a) for alignment of types
and variables is not compatible with MSVC. There is only a single
location accepted by both toolchains.

For variables standard C11 offers alignas(a) supported by conformant
compilers i.e. both MSVC and GCC.

For types the standard offers no alignment facility that compatibly
interoperates with C and C++ but may be achieved by relocating the
placement of __rte_aligned(a) to the aforementioned location accepted
by all currently supported toolchains.

To allow alignment for both compilers do the following:

* Move __rte_aligned from the end of {struct,union} definitions to
  be between {struct,union} and tag.

  The placement between {struct,union} and the tag allows the desired
  alignment to be imparted on the type regardless of the toolchain being
  used for all of GCC, LLVM, MSVC compilers building both C and C++.

* Replace use of __rte_aligned(a) on variables/fields with alignas(a).

Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
---
 lib/lpm/rte_lpm.h  | 5 +++--
 lib/lpm/rte_lpm6.c | 8 ++++----
 2 files changed, 7 insertions(+), 6 deletions(-)

diff mbox series

Patch

diff --git a/lib/lpm/rte_lpm.h b/lib/lpm/rte_lpm.h
index f57977b..f311fd9 100644
--- a/lib/lpm/rte_lpm.h
+++ b/lib/lpm/rte_lpm.h
@@ -11,6 +11,7 @@ 
  * RTE Longest Prefix Match (LPM)
  */
 
+#include <stdalign.h>
 #include <errno.h>
 #include <stdint.h>
 
@@ -118,8 +119,8 @@  struct rte_lpm_config {
 /** @internal LPM structure. */
 struct rte_lpm {
 	/* LPM Tables. */
-	struct rte_lpm_tbl_entry tbl24[RTE_LPM_TBL24_NUM_ENTRIES]
-			__rte_cache_aligned; /**< LPM tbl24 table. */
+	alignas(RTE_CACHE_LINE_SIZE) struct rte_lpm_tbl_entry tbl24[RTE_LPM_TBL24_NUM_ENTRIES];
+			/**< LPM tbl24 table. */
 	struct rte_lpm_tbl_entry *tbl8; /**< LPM tbl8 table. */
 };
 
diff --git a/lib/lpm/rte_lpm6.c b/lib/lpm/rte_lpm6.c
index 271bc48..ed5970c 100644
--- a/lib/lpm/rte_lpm6.c
+++ b/lib/lpm/rte_lpm6.c
@@ -98,16 +98,16 @@  struct rte_lpm6 {
 
 	/* LPM Tables. */
 	struct rte_hash *rules_tbl; /**< LPM rules. */
-	struct rte_lpm6_tbl_entry tbl24[RTE_LPM6_TBL24_NUM_ENTRIES]
-			__rte_cache_aligned; /**< LPM tbl24 table. */
+	alignas(RTE_CACHE_LINE_SIZE) struct rte_lpm6_tbl_entry tbl24[RTE_LPM6_TBL24_NUM_ENTRIES];
+			/**< LPM tbl24 table. */
 
 	uint32_t *tbl8_pool; /**< pool of indexes of free tbl8s */
 	uint32_t tbl8_pool_pos; /**< current position in the tbl8 pool */
 
 	struct rte_lpm_tbl8_hdr *tbl8_hdrs; /* array of tbl8 headers */
 
-	struct rte_lpm6_tbl_entry tbl8[0]
-			__rte_cache_aligned; /**< LPM tbl8 table. */
+	alignas(RTE_CACHE_LINE_SIZE) struct rte_lpm6_tbl_entry tbl8[0];
+			/**< LPM tbl8 table. */
 };
 
 /*